Pressure-control apparatus



1,512,932 s. H. HUNT PRESSURE CONTROL APPARATUS Filed Aug. 2, 1922 2 Sheets-Sheet 1 Gem-28. A 24.

S H. HUNT PRESSURE CONTROL APPARATUS Filed Aug. 2, 1922 2 Sheets-Sheet 2 Patented Oct. 28, 1924.

SYLVESTER H. HUNT, OF MILWAUKEE, WISCONSIN.

PRESSURE-CONTROL APPARATUS.

Application filed August 2, 1922. Serial No. 579,197.

To all whom it may concern: 7 I

Be it known that I, SYLVESTER'H. HUNT, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Pressure- Control Apparatus, of which the following is a specification.

The present invention relates to means for automatically maintaining a substantially zero pressure of the gases of combustion above the fire within a boiler furnace or other apparatus in which the control of pressure is desirable. r i

The object is to provide an apparatus. that is exceedinglysensitive to the variations in pressure and quick acting in the operation of the governing mechanism for controlling such pressure...

20 To that end heat instead of pressure is employed to'correct the pressure condition. within the furnace, so asto cause a substan-,

tially immediate operation of the control mechanism. This hasproven by actual; demonstration to be quicker than that type in which pressure is employed as the, actuating means for the initial'control device. v

In the accompanying drawings Figure 1 is a view. diagrammatic in itsv character of a well-known type of steam boiler and furnace with the pressure control mechanism inplace thereon,

Figure 2 is a'viewpartly'in front elevation and partly in section of the controlling member, i I v I Figure 3--is a longitudinal sectional View *at right angles to Figure 2.

In the embodiment di'scloseda' water tube boilerf4; is employed, having a furnace 5 and a st'ackG for the outlet of the products of combustion. In this stack is arranged a damper 7 for controlling the draft and obviously controlling the pressure of the gases in the furnace 5.

4 Mounted in one of the side walls of the furnace is an open-ended tube 8 that isin collar and space'the end wall 12 of said hood from the 'end' of the collar, leaving'an openv passageway 13 from the inner end of as shown at 17 to thecollar.

the collar 9 rearwardly to the atmosphere, i

as indicated by the arrows in Figure 3. The end wall 12 of the hood may be provided with a peep opening covered by a glass 14 that is held in place by a retaining ring 15, sothat a view through the tube and into the furnace can be obtained.

Surrounding the collar 9 and located within the hood 10 is a thermostatic ring 16 which may be of-any desired or well-known structure, this ring having one end fastened, Its other end carries a bracket '18 that extends outside the hood. This hood furthermore is provided in one side with chambers 19 and 20 having communication through a port 21. One of these chambers is adapted to receive fluid under pressure, preferably, air, from a pipe 22 connected thereto, and this fluid can obviously pass through the port 21 into the other chamber 20. The amount of air, however, is controlled by a suitable needle valve 23 that enters the port 21. A supply pipe 24: leads from the chamber 20 to suitable means for operating the damper 7. Thus inthe embodiment shown in Figure l, a motor diaphragm 25 is suitably mounted on the boiler structure and to the same is connected the pipe 24.. Lever mechanism 26 operated by said motor diaphragm is connected to the damper 7. The chamber 20 is furthermore provided with a vent port 27 opening through a nipple 28, and this nipple is controlled by a valve 29 adjustably mounted on the bracket 18.

It will be understood that the conduit or tube 8 has its inner end at or near the --place. where a zero pressure or so-called balanced draft is desired within the furnace, and it will be evident that if pressure occurs in said furnace there will be an outflow of the heated gases through the conduit 8 and hood 10 past the thermostatic 7 ring, as indicated by the arrows in Figure '3. As a consequence the ring will be heated and expanded thereby moving the valve 29 away from the nipple 28. Assuming that fluid under pressure is in the pipes 22 and 24, and that the motor diaphragm 25 is in an expanded position with'the damper 7 closed, the relief of the fluid through the nipple 28 will permit the collapse of the diaphragm 25, thereby opening the damper 7 and relieving the pressure sincethe products of combustion can then flow more freely outlet, of a damper for controlling the 1 from the stack 6. On the other end, if negative presS-ureoccurs in the furnace atmospheric air will flow inwardly through the hood 10 and conduit 8 into the furnace. This will cool the thermostatic ring 16, cansing it to contract and thereby seat the valve 29 upon the vent nipple 28. Pressure will consequently build up immediately in the pipe 24:, causing the operation of the motor diaphragm to close the damper 7. It will thusbe evident that the degree of opening or closing of the damper is in proportion to the time either hot or cool air is passing over the thermostat, and due to the very small amount of pressure required to force the heated or cold gases over the thermostat, the event of pressure change within the furnace is transmitted to the damper *more quickly than is the case where direct pressure is employed for actuating the parts. From the foregoing, it is thought that the construction, operation and many advantages of the herein described invention will be apparent-to those skilled in the art, without further description, and it will be understood that various changes in the size, shape, proportion and minor "details of construIct-ionmay be resorted to without departing from the spirit or sacrificing any of the advantages of the nvention.

Having thus fully described my inven tion, what I claim as new, and desire to secure by Letters Patent, is a 1. In apparatus of the character set forth, the combination with a furnacehaving an the of combustion escape of products through said outlet, means for operating the damper, including a heat-actuated controlling element, and means governed by the pressure in the furnace for supplying heat from the furnace to the heat-actuated element and removing it therefrom.

2. In apparatus of the character set forth, the combination with a furnace having an outlet, of means for controlling said outlet, a passageway communicating with the furna ce and allowing the influx and effluence of fluids of different temperature, a device an hezit-transferring relationship to the said fluids and actuated by a change in temperature, and mechanism controlled by said 'de-- vice for operating the outlet controlling means.

3. i In apparatus of the character set forth,

the combination with a furnace having an outlet, of means' forcontrolling said outlet, -{a passageway communicating with the furna'ce and allowing the influx and efliuence of fluids of different temperature, a thermostat in' heat-transferring relationship to the said fluids and actuated by achange'in tem- "yperature, and mechanism controlled by said fthermostat for operating the outlet controlling means. 4

controlling means.

5. In apparatus of the character set forth, the combination with a furnace having an outlet, of means for controlling said outlet, a passageway communicating with the interior. of the furnace and with the outside atmosphere and permitting the. inflow of the latter and the outflow of the heated furnace gases, a thermostat in heat transferring relation to the air or gases flowing through the passageway, and operating mechanism for the outlet controlling means controlled by the thermostat. V c

6. In apparatus of the character set forth, the combinationwith a furnace having an outlet, of means for controlling said outlet, a passageway communicating with the inte-' rior ofthe furnace and with the outside atmosphere and permitting 'the inflow of the latter and the outflow of the heated furnace gases, a thermostat in heat-transferringrelation to the air or gases fiowingthrough the passageway, fluid-actuated mechanism for operating the outlet controllingmeans, and means actuated by the thermostat for controlling the fluid for actuating said mechanism. Y f o "7. In apparatus'of the character fsetforth, the combination with a furnace having an outlet, of means for controlling said outlet, a passageway communicating with the'inte rior of the furnace and'with the outside at mosphere and permitting the inflow-ofthe latter and the outflow ofthe heated furnace lation to the air'or gases flowing through the passageway, fluid actuated mechanism for" operating theoutlet controlling means having a vent port, and a closure for said port operated by the'thermostat.

8. The combination with a chamber and means forcreating pressure therein, of a device for controlling said pressure, actuating mechanism for said device includin'g an initial controlling element comprising" a'heatactuated element, and means governed by the difference in pressure in said chamber for respectively supplying heat to the heatac- .tuatedelement and abstracting heat from said heat-actuated element.

9. The combination with a conduit open to the alternate flow of fluids of difi'erenttemperatures respectively in opposite directions, of a heat-actuated element operable in opposite directions and in-heat transferring relation to the fluids passing-in opposite directions through the 'conduita'nd oppositely operated by the heat of the fluids flowing in opposite directions, and controlling means operated by said heat-actuated element.

10. The combination with a conduit open to the alternate flow of fluids of different temperatures in opposite directions and comprising a pipe and a hood encircling the pipe, in communication therewith and open to the free flow of fluid in opposite directions therethrough, and mechanism for controlling the opposite flow or" such fluids including an oppositely operating thermostatic element in the hood operated in one direction by the heat of the fluid flowing in one direction and in the opposite direction by the heat of the fluid flowing in the opposite direction. I

11. The combination with a pipe, of a hood surrounding and in communication therewith and open to atmosphere, a thermostatic ring in the hood around the pipe, a fluid conduit connected with the hood, and a valve for said fluid conduit actuated by the rim".

1 2. The combination with a pipe, of a collar fixed upon one end thereof, a hood having spaced internal lugs mounted on the collar, a thermostatic ring surroimding the collar within the hood, a fluid chamber on the hood having a vent, and a valve controlling the vent and operated by the ring.

In testimony whereof, I affix my signature in the presence of two witnesses.

SYLVESTER H. HUNT. Witnesses:

P. J. KoRrsoH, A. D. DEsH. 

